Process of bucking or bleaching vegetable fibers dyed with vat dyestuffs.



rnrnnmcn cm mm, or 'i-rocnsrr-onsrnn-mam, GERMANY, assrenon. T nannwnnxn vonm. MEISTEB LUCIUS a nntrmne, on HooHsnoN-rHE-MAm, GERMANY,

A. CORPORATION OF GERMANY. I

rnocnssor :audxme on. iannacmne VEGETABLE FIBERS nYnn WITH var nrns'rurrs.

No Drawing.

To all whom it may concern:

Be it known that I, FRIEDRICH CARL THE-IS, a citizen of the Empire of Germany, residing at Hochst-on-the-Main, Germany, have invented certain new and useful Improvements in the Process of Bucking or Bleaching Vegetable Fibers Dyed with Vat Dyestuffs, of which the following is a specification.

Vegetable fibers dyed with vat dyestuffs have the drawback of, bleeding into the white parts when they are bucked with caustic soda, carbonate of soda and the like, which is often necessary in bleachinng dyed fabrics. It has been attempted to remedy this disadvantage by dilferent means for instance by adding permanganate or blchromate to the lye. Thus the bleeding of the dye into the undyed fibers (8pm or woven has been prevented, but the fibers were stamed by pre- 0 cipitates of metallic oxid and had then to be bleached by treatment with an acid. For instance in French Patent No. 392,858 is de-.

scribed a process for bucking material dyed or printed with vat dyestuffs, which consists in adding easily reducible substances toprevent the bleeding of the dye, for'whichpurpose exclusively certain organic compounds are used, whereas the processof the present invention consists in using a certain inor game body which, contrary to the other inor anic substances which have been hitherto I tried, prevent the bleeding of the dye withto 0.5 kgr. of bromate of potash. About 500 kilograms of water is generall used for each 100 kilograms of the fabric. In this lye the material is boiled for two hours or longer, with or without pressure, according to the usual method of bleaching.

Having now particularly described my invention, what I claim is: Q

The process of bleaching vegetable fibers or fabrics dyed with vat-d estutfs avoiding the bleeding of the dye into the undyed portions, which" consists in subjecting the dyed materials to the action of a boiling. alkaline solution containing alkali-bromate' In testimony whereof, I afiix my signature in presence of twowitnesses. FRIEDRICH CARL THEIS.

- Witnesses:

JEAN Gmmn, CARI. GRUND.

Specification of Letters mtent. Patented Feb. 1%, 1911. Applicationfiled October 22, 1909. Serial No. 523,969. 

